1. Field of the Invention
The present invention relates to a display control apparatus and display control method that can change a driving frequency (frame rate).
2. Description of the Related Art
A technique is known in which the frame rate (60 Hz) of broadcast waves is changed to the display driving frequency (120 Hz or 240 Hz) in a double-speed drive system. For example, Japanese Patent Application Laid-Open No. 2001-42831 discusses increasing the frame rate of a display image to be higher than the frame rate of an input image signal to improve quality of the display image.
However, if the frame rate is increased, a region that needs to be brightly displayed may be perceived to be dark in the display image.
For example, even when a luminous intensity per unit time is maintained at a certain level, if the luminous frequency of a display screen is changed, brightness of the display screen may be perceived differently. One of the causes for this phenomenon is that humans' perceptual sensitivity to brightness differs depending on the luminous frequency. Thus, for example, when the frame rate of an input image signal is 60 Hz, if the output frame rate (driving frequency) is changed to 120 Hz, the image may be perceived to be more dark, compared with the image displayed at 60 Hz.
Thus, for example, when a display image includes a region that needs to be displayed brightly (such as a starry sky or a firework), if the frame rate is increased and the image is thus displayed darkly, observers may perceive that the image quality has been deteriorated.